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CVE-2026-89520

Estado: RecibidaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

sched/core: Make core-sched flips wait for in-flight selections

Core scheduling's pick_next_task() operates on all sibling rqs under one acquisition of the shared core-wide lock. A ->pick_task() that releases the rq lock leaves every sibling __lock momentarily free, letting __sched_core_flip(false) complete mid-selection and rebind rq_lockp() under it. The selection resumes on the split locks, touching sibling state it no longer protects, and __schedule() finally releases a lock that was never taken while leaking the one that was.

Leer descripción completaMostrar menos

Count in-flight core-wide selections in the leader's rq->core_pick_in_flight and make __sched_core_flip() wait for the count to drain. The count only changes under the shared lock, which the flip holds while sampling, so no other ordering is needed. The wait can repeat while selections overlap, but the flip backs off between samples and flips are rare cookie-lifetime events.

sched_core_cpu_deactivate() moves the count to the new leader - a stale copy left behind would bias it forever if that CPU later returns as its own leader.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad local en el kernel Linux (AV:L, PR:L) que permite escalada de privilegios mediante condición de carrera en core-sched, causando corrupción de memoria y DoS potencial (I:H, A:H).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-89520",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "lessThan": "3e2511bffa93a639774a99e392181e21d28677e2",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "lessThan": "9d69422ddaa13526c2223444e237d948d6e44728",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "lessThan": "23eda24f325a6e6d686d30ec75f2e9d6745e2015",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "539f65125d20aacab54d02d77f10a839f45b09dc",
              "lessThan": "f3629c63a4af3e491381780bc6c123cb498c4c40",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "kernel/sched/core.c",
            "kernel/sched/sched.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.14"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.14",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "kernel/sched/core.c",
            "kernel/sched/sched.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:34.647",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/23eda24f325a6e6d686d30ec75f2e9d6745e2015",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/3e2511bffa93a639774a99e392181e21d28677e2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9d69422ddaa13526c2223444e237d948d6e44728",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f3629c63a4af3e491381780bc6c123cb498c4c40",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/core: Make core-sched flips wait for in-flight selections\n\nCore scheduling's pick_next_task() operates on all sibling rqs under one\nacquisition of the shared core-wide lock. A ->pick_task() that releases the\nrq lock leaves every sibling __lock momentarily free, letting\n__sched_core_flip(false) complete mid-selection and rebind rq_lockp() under\nit. The selection resumes on the split locks, touching sibling state it no\nlonger protects, and __schedule() finally releases a lock that was never\ntaken while leaking the one that was.\n\nCount in-flight core-wide selections in the leader's rq->core_pick_in_flight\nand make __sched_core_flip() wait for the count to drain. The count only\nchanges under the shared lock, which the flip holds while sampling, so no\nother ordering is needed. The wait can repeat while selections overlap, but\nthe flip backs off between samples and flips are rare cookie-lifetime\nevents.\n\nsched_core_cpu_deactivate() moves the count to the new leader - a stale copy\nleft behind would bias it forever if that CPU later returns as its own\nleader."
    }
  ],
  "lastModified": "2026-10-03T11:17:42.710",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}